Figure 5.

Fluence/response curves of H. salinarum strain Pho81Wr⁻ expressing various constructs listed in Fig. 1. A 1-sec pulse of 500 nm light was used for stimulation of the cells. 100% intensity was 6 × 10⁴ ergs⋅cm⁻²⋅sec⁻¹ and light intensity was attenuated with neutral density filters. The phototaxis index is calculated in sec⁻¹ as the integral of the swimming reversal frequency measured by motion analysis over the first 1 sec after the stimulus minus the integral over 1 sec starting from 6 sec after the stimulus was initiated.